Formation, Stability and Cytotoxicity of Precursor Microemulsions to Prepare Core‐Shell Polymeric Nanoparticles for Pharmaceutical Applications

The preparation of biocompatible normal (oil‐in‐water, o/w) microemulsions (ME) with different oil phases (peppermint oil, trans‐anethole, vitamin E, jojoba oil) and stabilized with d‐α polyethylene glycol succinate (TPGS‐1000) and isobutanol (iso‐BuOH) is presented. Results of average particle diameter determination, Dp, indicated 6.35 ≤ Dp ≤ 10.24 nm. These ME showed excellent colloidal stability (−40 and +40 °C) and, without any drug loaded, decreased dramatically the viability of leukemia cells (K562), 60–90 %, in 24 hours. Besides, this behavior was potentiated when paclitaxel (PTX, an anticancer drug) was loaded in the transanethole microemulsion, where the cell viability decreased until 2 % at 0.5 μg/mL of PTX. These MEs are precursors to synthetize polymeric nanocapsules when coated with a thermo or pH – sensible polymer with potential for cancer treatment.